Diagnostic practices for patients with shortness of breath and presumed obstructive airway disorders: a cross-sectional analysis

Ross T. Tsuyuki; William Midodzi; Cristina Villa-Roel; Darcy Marciniuk; Irvin Mayers; Dilini Vethanayagam; Michael Chan; Brian H. Rowe

doi:10.9778/cmajo.20190168

Article Figures & Tables

Figures

Tables

Download figure
Open in new tab
Download powerpoint
Figure 1:
Flow of patients through the study. *By patient report and medical record review. Note: COPD = chronic obstructive pulmonary disease, OAD = obstructive airway disorder, PFT = pulmonary function test, SOB = shortness of breath.

Tables

Figures

Table 1:

Criteria for study diagnosis of obstructive airway disorders in patients with shortness of breath

Disease	Study diagnosis	Criteria (4), (5)
Asthma	Definite asthma	Increase in FEV₁ > 200 mL and > 12% above prebronchodilator FEV₁ OR Positive response to methacholine provocation test: an airway hyperresponsiveness as defined by use of PC₂₀
Asthma	Probable asthma	Diagnosis by two-thirds consensus of the expert physician panel from review of examination, current respiratory symptoms and prior medical records
COPD	Definite COPD	Postbronchodilator FEV₁ < 80% predicted together with an FEV₁/FVC < 0.70
COPD	Probable COPD	Diagnosis by two-thirds consensus of the expert physician panel from review of examination, current respiratory symptoms and prior medical records
Non-OADs	Probable normal or with other entities	Does not fulfill criteria for definite or probable asthma or COPD diagnoses^*

Note: COPD = chronic obstructive pulmonary disease, FEV₁ = forced expiratory volume in 1 second, FVC = forced vital capacity, OAD = obstructive airway disorder, PC₂₀ = the provocative concentration of methacholine that results in a 20% drop in FEV₁.
↵* In patients with a brain natriuretic peptide measurement > 100 pg/mL, a cardiologist consultation was obtained to evaluate the patient for heart failure.

Table 2:

Characteristics of patients with shortness of breath referred by pharmacists

Characteristic	No. (%) of patients^* n = 328
Age, yr, median (IQR)	50 (32–64)
Weight, kg, mean ± SD	83.3 ± 20.7
Height, cm, mean ± SD	166.4 ± 9.6
Sex, female	188 (57.3)
Ethnicity
White	283 (86.3)
South Asian	19 (5.8)
Aboriginal	12 (3.6)
Other^†	14 (4.3)
Highest level of education
Completed postsecondary education	161 (49.1)
Some postsecondary education	62 (18.9)
High school diploma	61 (18.6)
Less than grade 12	44 (13.4)
Married or common-law status	190 (57.9)
Most common comorbidities
Allergies	255 (77.7)
GERD	142 (43.3)
Depression	104 (31.7)
Sinus or nasal polyps	103 (31.4)
Anxiety	88 (26.8)
Other relevant comorbidities
Hypertension	85 (25.9)
Anemia	42 (12.8)
Coronary artery disease	28 (8.5)
Heart failure	6 (1.8)
Smoking history
Current	65 (19.8)
Former	117 (35.7)
Never	146 (44.5)
Pack-years for current or former smokers, median (IQR)	19 (10–31)
Symptoms
Cough symptoms (day or night)	98 (29.9)
Sputum production	56 (17.1)
Chest tightness	64 (19.5)
Wheeze	64 (19.5)
Other symptoms
Peripheral edema	31 (9.5)
Fatigue	70 (21.3)
Bilateral ankle edema	34 (10.4)
Fever or flu-like symptoms	18 (5.5)
Currently absent from work or school	23 (7.0)
Previously diagnosed by a primary care provider for SOB symptoms	216 (65.8)
Asthma	181/216 (83.8)
COPD	34/216 (15.7)
Other	113/216 (52.3)
Previously seen by a specialist for SOB	128 (39.0)
Previously had PFTs conducted for SOB	134 (40.8)

Note: COPD = chronic obstructive pulmonary disease, GERD = gastroesophageal reflux disease, IQR = interquartile range, PFT = pulmonary function test, SD = standard deviation, SOB = shortness of breath.
↵* Unless stated otherwise.
↵† Included black, Hispanic, East and Southeast Asian, Middle Eastern and other ethnicities not stated in the case report form.

Table 3:

Medications^* used by patients previously diagnosed with asthma and chronic obstructive pulmonary disease, by diagnosis

Medication	No. (%) of patients
Medication	Previous diagnosis of asthma n = 181^†	Previous diagnosis of COPD n = 34^†	No previous diagnosis of asthma or COPD n = 127
Short-acting β-agonist	141 (77.9)	22 (64.7)	83 (65.4)
Inhaled corticosteroid	45 (24.9)	3 (8.8)	38 (29.9)
Inhaled corticosteroid–long-acting β-agonist	120 (66.3)	30 (88.2)	54 (42.5)
Oral corticosteroid	6 (3.3)	2 (5.9)	5 (3.9)
Long-acting anticholinergic	7 (3.9)	13 (38.2)	7 (5.5)
Short-acting anticholinergic	5 (2.8)	2 (5.9)	6 (4.7)
Theophylline	4 (2.2)	1 (2.9)	1 (0.8)
Leukotriene antagonist	20 (11.0)	2 (5.9)	5 (3.9)

Note: COPD = chronic obstructive pulmonary disease.
↵* Based on pharmacist report.
↵† A total of 14 patients (4.3% of the study population) reported a previous diagnosis of both asthma and COPD.

Table 4:

Adjudicated diagnoses by expert physician panel for patients with shortness of breath referred by pharmacists

Diagnosis by expert physician panel	No. (%) of patients n = 328
Asthma^*	149 (45.4)
Definite diagnoses	147/149 (98.7)
Probable diagnoses	2/149 (1.3)
COPD^*	97 (29.6)
Definite diagnoses	94/97 (96.9)
Probable diagnoses	3/97 (3.1)
Other	20 (6.1)
Heart failure	9/20 (45.0)
Restrictive lung diseases or pulmonary hypertension	8/20 (40.0)
Bronchitis	2/20 (10.0)
Obesity	1/20 (5.0)
Unknown origin (indeterminate cause for SOB)	62 (18.9)

Note: COPD = chronic obstructive pulmonary disease, SOB = shortness of breath.
↵* A total of 11 patients had both asthma and COPD diagnoses.

Table 5:

Agreement between diagnoses of asthma and chronic obstructive pulmonary disease by primary care providers and those derived from pulmonary function testing

		PFT-derived diagnoses

		Asthma^*			COPD^*

		Yes	No	Total	Yes	No	Total
Prior diagnosis of OAD by PCP	Yes	106	87	193	27	11	38

	No	43	92	135	70	220	290

	Total	149	179	328	97	231	328

	PPV, %		54.9			71.1

	NPV, %		68.1			75.9

	κ value		0.22			0.28

	p value		< 0.001			< 0.001

Note: COPD = chronic obstructive pulmonary disease, NPV = negative predictive value, OAD = obstructive airway disease, PCP = primary care provider, PFT = pulmonary function testing, PPV = positive predictive value.
↵* A total of 11 patients had both asthma and COPD diagnoses.